Abstract

Introduction: Adenocarcinoma is currently the most common type of lung cancer. Mutations in EGFR are predictive of TKIresponseandmutuallyexclusivewithmutationsin KRAS. Molecularanalysisoffreecirculating DNA (cfDNA) has promised to be a useful tool for making these determinations. This study compares two different techniques for determining mutations in KRAS and EGFR in biopsy and blood samples from patients with lung adenocarcinoma. Patients and Method: Patients with suspected lung cancer were included and plasma and serum samples were obtained. When the diagnosis of adenocarcinoma was confirmed, the mutational status of EGFR and KRAS in biopsies, plasma and serum were analyzed by COBAS® KRAS/EGFR Mutation Tests and SSCP (Single Stranded Conformational Polymorphism) and confirmed by Sanger's sequencing. Results: Seven patients out of 19 had mutations detected on COBAS® and SSCP biopsy: 3 in EGFR and 4 in KRAS. EGFR mutations were detected in 2 patients in stage I and 1 in stage IV. Those of KRAS 1 in adenocarcinoma in situ, 2 in stage I and 1 in stage IV. Only one mutation was detected in plasma-derived cfDNA (KRAS, stage IV), observing a correlation of 14% between biopsy and cfDNA (1/7). Discussion: The COBAS® technique allowed to detect mutations in plasma cfDNA. Both SSCP and Sanger sequencing and COBAS® techniques allowed the detection of mutations in biopsies. cfDNA could be used to detect mutations lung adenocarcinomas.